"I think we now know why beans rallied so much yesterday, too. It is Brazil and the logistics. I think I saw today that it (Brazil) exported like 900,000 tons of soybeans in February, from 1.6 million last year," Scoville says.

The U.S. does not have that much to sell. "Therefore, flat price and spreads were well supported today. Corn and wheat are along for the ride," Scoville says.

"As long as China keeps buying US beans for near term shipment off Brazilian port shipping delays, fund psychology is the price has to move high enough to shut off demand and ration our historically tight US beans stocks," Hannagan says.

With corn, there are ports worldwide to buy corn at any price but exportable beans are only found in the US and South America, he says.

"Watch the daily demand releases closely as any shift to or away from US ports will give us a sharp rally or break near-term. The long-term into March and in early April looks to be supply side priced and futures bearish," Hannagan says.